1. Field of the Invention
The present invention relates to an addition reaction curable organopolysiloxane composition, and in particular to an addition reaction curable organopolysiloxane composition which displays good adhesion to cured products of condensation reaction curable silicone rubbers, and is useful as a sealing material, a potting material, a coating material, and particularly as a coating material for preventing the adhesion of aquatic organisms to ships.
2. Description of the Prior Art
The intermolecular forces in organopolysiloxanes are small (that is, the cohesive strength between molecules is small), and as a result, silicone rubber materials typically display excellent releasability, although on the other hand, they tend to display rather poor adhesion to substrates.
Accordingly, in order to produce addition reaction curable silicone rubber adhesives with good adhesion to a variety of substrates, much research has been conducted into the addition of adhesion imparting components to addition reaction curable organopolysiloxane compositions, as a way of generating good adhesion. For example, the use of organohydrogensiloxanes containing an epoxy group (Japanese Post-Examination Patent publication (kokoku) No. 53-13508 (JP53-13508 B)), corresponding to U.S. Pat. No. 4,077,943, and organohydrogensiloxanes containing an epoxy group and an alkoxysilyl group (Japanese Post-Examination Patent publication (kokoku) No. 59-5219 (JP59-5219B)) has already been disclosed. These techniques enabled the adhesion of conventional addition reaction type silicone rubber adhesives to metals and resins and the like to be improved considerably, although even these compositions displayed absolutely no adhesion to cured products of condensation reaction curable silicone rubber, and a resolution to this problem has been keenly sought.
Japanese Patent Publication No. 3232009 (JP3232009B), corresponding to U.S. Pat. No. 5,854,344, discloses the addition of an organopolysiloxane containing a silanol group to an addition reaction curable composition, although the object and effect of this addition is to improve the redispersibility of a precipitated inorganic filler, and moreover, Japanese Patent Publication No. 3184231 (JP3184231B), corresponding to EP 497,277A, discloses the addition of an organopolysiloxane represented by a formula CH2═CH(CH3)2SiO[(CH3)2SiO]3Si(OCH3)3 to a silicone rubber composition, although the object and effect of this addition is to generate a cured product with excellent durability to repeated deformation such as bending or elongation, and in both cases, no mention is made of improving the adhesion relative to a condensation reaction curable silicone rubber cured product.